Jesus was a real person but he was not god nor the Messiah he was just a normal man who thought he was god

I'm wondering where the stories about kid jesus stealing the ineffable name of god and putting it in his leg came from.

Which Jesus? That was a very common name back then although there's never been ANY evidence shown to support that he actually did exist, in human form. Richard Carrier's book, On the Historicity of Jesus, along with David Fitsgerald's book, Nailed, literally put the nails in that coffin.